What is Conjugated Linoleic Acid (CLA)?
Conjugated linoleic acid, or CLA, is a type of fatty acid found primarily in animal products derived from ruminants like cows, goats, and sheep. Unlike industrially produced trans fats, the CLA in these foods is a natural trans fat that is formed during the animal's digestive process. This process is most active when animals consume green, leafy plants, which is why the CLA content in their meat and dairy is so dependent on their diet. This distinction is crucial, as the isomers of CLA found in food are different from those in most supplements, and are widely regarded as beneficial.
The Best Natural Sources of CLA
The highest concentrations of CLA are consistently found in the fat of grass-fed animals and their byproducts. Prioritizing these sources is the most effective way to increase your dietary intake of this fatty acid.
High-CLA Food List:
- Grass-Fed Beef: The beef from cattle that graze on fresh pasture contains significantly more CLA than that from grain-fed cattle, sometimes as much as two to three times more. The fattier cuts will have the highest concentration, as CLA is stored in the fat cells. Cooking beef also increases the concentration of CLA, likely due to moisture loss.
- Lamb: Often cited as one of the richest food sources of CLA, particularly when the animal has grazed on natural grasses. The amount of CLA per gram of fat can be higher in lamb than in beef.
- Grass-Fed Butter: Butter from grass-fed cows is a highly concentrated source of CLA, containing substantially more than conventional butter. It is an easy way to add CLA to your diet through cooking or as a topping.
- Fermented Dairy Products: Fermentation by certain bacteria, like those used to make cheese and yogurt, can also boost CLA levels. Some cheese types, including Blue, Swiss, and ripened cheeses, are noted for higher concentrations.
- Full-Fat Dairy: Full-fat versions of dairy products like milk, yogurt, sour cream, and cottage cheese from grass-fed cows are excellent sources of CLA. The CLA resides in the milk fat, so skim or low-fat versions will contain very little.
CLA Content in Grass-Fed vs. Grain-Fed Products
The diet of ruminant animals is the most critical factor determining the CLA content of their products. This is clearly demonstrated when comparing the fatty acid profiles of grass-fed versus grain-fed livestock.
| Feature | Grass-Fed Ruminants | Grain-Fed Ruminants |
|---|---|---|
| CLA Content | Significantly higher (2-5x more) | Lower |
| Omega-3 Content | Higher | Lower |
| Overall Fat Content | Generally leaner, but higher-fat portions still rich in CLA | Often higher total fat |
| Antioxidants | Higher levels (e.g., Vitamin E) | Lower |
| Primary Diet | Fresh forage, pasture | Grains and supplements |
Can You Get CLA from Plant-Based Foods?
While ruminant products are the most potent sources, small amounts of CLA are also found in some plant-based sources. For vegetarians or vegans, these can provide a limited dietary intake, though they are not comparable to the levels found in grass-fed meat and dairy.
- Certain Vegetable Oils: Safflower oil and sunflower oil are known to contain small amounts of CLA precursors. The body can synthesize a small amount of CLA from dietary linoleic acid.
- Mushrooms: White button mushrooms are one of the few plant-based foods that contain a minor amount of CLA.
Cooking and Maximizing CLA Intake
Cooking your food can affect its nutrient profile, and this is true for CLA. Studies on beef indicate that cooking can increase the total CLA concentration in the meat due to moisture loss. High-temperature cooking methods may result in slightly higher CLA levels. However, CLA isomers show high stability during thermal processing, so cooking is not a major concern for preserving content. For best results, consider these tips:
- Choose Wisely: Always opt for grass-fed and pasture-raised products when possible to maximize natural CLA content. Look for fat content, as CLA is stored in the fat.
- Cook for Concentration: Cooked beef often has higher CLA levels per gram due to water reduction. Don't be afraid to cook to your preference, as the CLA is relatively stable.
- Embrace Fermented Products: Add cheeses like Blue or Swiss, or full-fat yogurt, to your diet to benefit from the CLA-enhancing effects of fermentation.
Conclusion
For those seeking to increase their intake of conjugated linoleic acid, the most effective strategy is to focus on natural dietary sources, particularly grass-fed meat and dairy products. Lamb, grass-fed beef, and butter from pasture-raised animals offer the highest concentrations. While supplements exist, the CLA from whole foods provides a more natural profile and comes alongside other beneficial nutrients. By making conscious choices about the sourcing and type of animal products consumed, you can effectively enhance your CLA intake as part of a balanced diet.
This authoritative article provides further insight into the benefits and food sources of CLA: Conjugated linoleic acid (CLA): Sources, uses, and benefits.
